The hCG diet is two things sold together: a daily dose of human chorionic gonadotropin — a pregnancy hormone — and a diet of about 500 calories a day. It is one of the oldest weight-loss claims attached to any peptide hormone, and one of the most thoroughly tested. This page sets out where it came from, what the controlled trials found, and what US regulators have done about it.
What hCG is approved for is on our hCG for men page and the label's dose tables on our hCG dosage page, which also explains why most hCG products in FDA's label database are diet drops. Side effects are on our hCG side effects page. GLP-1 drugs, which are approved for weight loss, are a different question entirely and are covered by GLP1Ledger. Nothing here is a recommendation.
Where it came from
In November 1954 The Lancet published a two-page paper, "The action of chorionic gonadotrophin in the obese", by A.T.W. Simeons (PMID 13213083; the record carries no abstract). It proposed small daily hCG injections alongside a diet of about 500 calories. It was a report from his own practice, not a controlled trial. The three benefits later attributed to the method — more weight lost than the diet alone, less hunger, and fat lost from the "wrong" places — are the three claims the trials below set out to test and the three the US labels now deny.
What every hCG label says first
The current Fresenius Kabi chorionic gonadotropin label (DailyMed, effective 11 April 2025, read 20 October 2026) puts this sentence, in capitals, before its list of indications:
hCG has not been demonstrated to be effective adjunctive therapy in the treatment of obesity. There is no substantial evidence that it increases weight loss beyond that resulting from caloric restriction, that it causes a more attractive or "normal" distribution of fat, or that it decreases the hunger and discomfort associated with calorie-restricted diets.
Each clause answers one of Simeons' three claims. The same statement opens the Pregnyl and Novarel labels (openFDA label records, read 20 October 2026). It is unusual for a label to rule out an unapproved use this directly; it was written because the use was common.
The trials
| Trial | Design | Who | Result |
|---|---|---|---|
| Asher and Harper 1973 | Double-blind, hCG vs placebo, 500-kcal diet | Obese patients (no abstract on record; result as summarised by Stein 1976) | Significantly greater weight loss and less hunger on hCG — the positive trial Stein et al. set out to replicate |
| Stein et al. 1976 | Randomised double-blind replication of Asher–Harper, 32 days | 51 women (41 completed) | No difference in weight loss, waist and hip, or hunger |
| Young et al. 1976, JAMA | Double-blind randomised crossover | 202 people | No difference in any phase (p > 0.1) |
| Shetty and Kalkhoff 1977 | Inpatient, 500-kcal diet, 125 IU daily for 30 days | 11 obese women | Weight loss "nearly identical"; no difference in skinfolds or circumferences |
| Bosch et al. 1990 | Double-blind, placebo-controlled, 6 weeks | 40 obese women | No advantage on any variable, including hunger |
| Lijesen et al. 1995 | Criteria-based meta-analysis | 8 controlled + 16 uncontrolled trials | "No scientific evidence" hCG is effective for obesity |
Sources: PMIDs 4574032, 786001, 792477, 836112, 2405506, 8527285, records read 20 October 2026.
The pattern is the instructive part. The 1973 positive trial was taken seriously enough that another team copied its diet and protocol exactly — and found nothing. The 1977 inpatient study removed the question of whether people were sticking to the diet: the women were in hospital, eating identical meals, and the hormone made no difference to weight, body measurements, or blood and urine chemistry. The Bosch trial went further and found weight loss on its diet "similar to that on severely restricted intake" — the diet did the work. The 1995 meta-analysis scored every trial it could trace for method quality; the better the trial, the more consistently it was negative. Of the 12 scoring 50 or more out of 100, all controlled, one called hCG a useful adjunct.
The census behind this page was a PubMed search on 20 October 2026 for hCG in the title, an obesity or weight term in the title, and trial or meta-analysis publication types: 13 records, of which the six in the table test the diet. No trial since 1995 was found.
What regulators did
The drops. By 2011 much of the diet was sold as over-the-counter oral drops, pellets and sprays, many labelled "homeopathic". In late 2011 FDA and FTC sent joint warning letters to sellers. The FTC's legal library records a joint FDA/FTC warning letter "concerning product labeling" for hCG drugs, dated 28 November 2011, to HCG Diet Direct LLC, signed for FDA by its Denver District Office and Office of Compliance.
The lawsuit. In January 2014 the FTC sued HCG Diet Direct and its owner in federal court in Arizona (case 2:14-cv-00015), alleging deceptive advertising of its homeopathic drops; it settled with a stipulated judgment. In February 2016 the court lifted the suspension of that judgment — an FTC release headline said the ruling allowed the agency to try to collect up to $3.2 million.
The consumer warning. FDA's page "Avoid Dangerous HCG Diet Products" (content current as of 13 July 2020, read 20 October 2026) advises consumers to avoid hCG weight-loss products sold as drops, pellets and sprays online, in weight-loss clinics and in some shops. It states hCG is approved only as a prescription drug for female infertility and certain other conditions, not for weight loss, and quotes an FDA official that "any loss is from severe calorie restriction. Not from the HCG."
The risk the diet itself carries
FDA's page puts the danger mainly in the diet. Very-low-calorie diets of the kind these products promote carry risks of gallstones, electrolyte imbalance affecting muscle and nerve function, and irregular heart rhythm; the agency calls them "dangerous, even potentially fatal" without medical supervision, and notes people may not get enough protein, vitamins and minerals. Prescription hCG adds its own label warnings — gynecomastia, fluid retention, and in women ovarian hyperstimulation and blood clots — set out on our side effects page.
What the record does not contain
- A controlled trial since 1990 showing hCG adds anything to calorie restriction.
- Any approved hCG product for weight loss in the United States.
- Evidence that hCG changes where fat is lost, or reduces hunger, in a blinded comparison.
- A published assay of what over-the-counter hCG drops actually contain.
A doctor or registered dietitian is the person to assess any very-low-calorie diet for an individual.
Sources and dates
Read 20 October 2026: Fresenius Kabi chorionic gonadotropin label (openFDA, set f93b2baa-03ac-4650-b35a-20b818d712d6); PubMed records for PMIDs 13213083, 4574032, 786001, 792477, 836112, 2405506, 6340811 and 8527285; FDA consumer update "Avoid Dangerous HCG Diet Products"; FTC legal-library entries for the joint FDA/FTC warning letter to HCG Diet Direct LLC (28 November 2011) and FTC v. HCG Diet Direct, LLC (matter 122 3192).